Video output consumes a significant amount of power for a laptop or desktop computer. Other computing systems and electronics devices—such as handheld computing devices, cellular telephones and MP3 players—also devote a large fraction of their power budget to video. Power consumption sensitivity increases for portable devices that rely on a battery having limited energy supply.
Liquid crystal displays (LCD) are a widely adopted type of display device that includes a backlight and pixelated filters. The backlight typically emits white light that is filtered by red, green and blue (RGB) filtering elements for each pixel.
Current power conservation techniques alter an entire LCD image at once. These techniques uniformly shut down the backlight or assume a much lower backlight luminance level. This noticeably changes the video output, and often the backlight reduction is so drastic that it compromises a person's ability to see any graphics. The change is also markedly sudden, which coupled with the harsh change in luminance, draws the person's attention to the diminished graphics—and their inability to see them. Frequently, a person responds by reactivating the entire display, thereby returning the LCD to full power. As a result, minimal power is saved.
Based on the foregoing, it should be apparent that alternative power conservation techniques would be desirable.